DUBAI, Aug 2 (Reuters) - Buyout firms TPG and KKR & Co have emerged as leading contenders to run Dubai-based private equity firm Abraaj's troubled $1 billion healthcare fund, three sources familiar with the matter said. The two firms have access to the healthcare fund's virtual data room and are about to start due diligence, with offers expected in the next few weeks, two of the three sources said.

They have emerged as frontrunners from an initial list of six bidders, two of the sources said, adding that some had been told investors wanted a potential manager with a large balance sheet and the ability to handle multiple regulators.

One of the sources said TPG is trying to do the deal through its Rise Fund, its $2 billion impact investment vehicle which counts Irish rock star Bono among its founders.

TPG and KKR declined to comment. Abraaj's provisional liquidators, Deloitte and PwC, did not respond to Reuters' requests for comment.

The sources have declined to be identified because details of the sale process are not public.

Abraaj's healthcare fund has been at the centre of a dispute since investors such as the Bill & Melinda Gates Foundation and International Finance Corp (IFC) began questioning Abraaj on how it used some of its money.

This triggered months of turmoil at the Middle East and North Africa's biggest buyout fund, which halted its fundraising activities and shook up its management as it tackled ensuing debt repayment problems.

In June Abraaj filed for provisional liquidation in the Cayman Islands.

Abraaj has denied it misused the funds. Gates Foundation and IFC have declined to comment on the row.

Separately, Abraaj's joint provisional liquidators are seeking to sell part of its investment management business. Potential buyers for that process have until August 24 to submit their bids, said a separate source familiar with the matter.

AlixPartners is managing the fund and is also involved in the sale process, working closely with investors and Deloitte, the sources told Reuters. AlixPartners declined to comment.

Most investment professionals in the healthcare fund have left, although Khawar Mann, who leads the fund, is still there, two sources said.

Karachi-born Arif Naqvi established Abraaj with only $60 million in 2002 and built it into $13.6 billion emerging market champion, attracting money from the Gates Foundation and U.S. pension funds. He also became a champion for impact investing, which is aimed at delivering a social or environmental benefit alongside a financial return, arguing that private capital can tackle some of the world's most pressing issues in the developing world.

Additional reporting by Joshua Franklin in New York; Editing
by Jan Harvey